未定義的方法`build_book_reservation

Question

嗨我只是想知道，如果，爲什麼會找不到刷新時我的預訂，並在其他控制器

用它，這是我的ApplicationController

helper :all # include all helpers, all the time 


    private 
def current_reservation 
    @reservation ||= Reservation.find(session[:reservation_id]) if session[:reservation_id] 
    #last assigned value will be returned as default. 
end 

def create_reservation_session(id) 
    session[:reservation_id] = id 
end 

def destroy_reservation_session 
    session[:reservation_id] = nil 
end 

和我在這裏想給我們這

def new 
    @book_reservation = BookReservation.new 
end 

def create 
    @reservation = current_reservation 
    @book_reservation=@reservation.build_book_reservation(params[:book_reservation]) 
    if @book_reservation.save 
    #If success set session 
    create_reservation_session(@reservation.id) 
    #redirect_to root_url, :notice => "Successfully created book reservation." 
    else 
    render :action => 'new' 
    end 
end 

它提出undefined method build_book_reservation」的零：NilClass`錯誤

---

模型/ book_reservation.rb

belongs_to :reservation 

模型/ reservation.rb

has_one :book_reservation 

Answer 1

錯誤的原因是你從來沒有設置會議，但您嘗試訪問it.In您的應用程序控制器使用

private 
def current_reservation 
    @reservation ||= Reservation.find(session[:reservation_id]) if session[:reservation_id] 
    #last assigned value will be returned as default. 
end 

def create_reservation_session(id) 
    session[:reservation_id] = id 
end 

def destroy_reservation_session 
    session[:reservation_id] = nil 
end 

在你的控制器

def new 
    @book_reservation = BookReservation.new 
end 

def create 
    @reservation = Reservation.find(params[:reservation_id]) 
    if @reservation 
    @book_reservation=@reservation.build_book_reservation(params[:book_reservation]) 
    if @book_reservation.save 
     #If success set session 
     create_reservation_session(@reservation.id) 
     #redirect_to root_url, :notice => "Successfully created book reservation." 
    else 
     render :action => 'new' 
    end 
    else 
     render :action => 'new' 
    end 

然後，每當你需要，你可以使用current_reservation 。

Answer 2

你永遠不要把:reservation_id了會議。

這意味着session[:reservation_id]是nil和Reservation.find(nil)引發了您所看到的異常。